The holographic optical elements (HOE) in dichromated gelatin (DCG) for airborne head-up displays are studied. The main characteristics of the HOEs are described. Some fabrication techniques of the HOEs in DCG are discussed. The large-size (max (Phi) 280) flat and spherical substrates HOEs used in our holographic head-up display prototype have been fabricated. The measured results of the HOE are as follows: approximately 95% peak diffractive efficiency, approximately 20 half spectral width and approximately 544 nm peak response wavelength.